1. Field of the Invention
The present invention relates generally to apparatus employed for providing high purity liquids. More particularly, the present invention relates to apparatus employed for storing and dispensing high purity liquids when providing high purity liquids.
2. Description of the Related Art
Microelectronic fabrications are formed from microelectronic substrates over which are formed patterned microelectronic conductor layers which are separated by microelectronic dielectric layers.
Common in the art of microelectronic fabrication is the use of high purity liquids, such as but not limited to high purity deionized water, high purity aqueous acids, high purity aqueous bases and high purity organic solvents, to effect fabrication of microelectronic fabrications. Within the art of microelectronic fabrication, such high purity liquids are typically characterized by dissolved and/or suspended detrimental impurity levels of less than about 100 parts per billion, and more typically and preferably such high purity liquids are characterized by dissolved and/or suspended detrimental impurity levels of less than about 100 parts per trillion.
High purity liquids are typically desirable, and often essential, within the art of microelectronic fabrication for fabricating microelectronic fabrications, since such high purity liquids typically provide microelectronic fabrication processes which provide minimal detrimental residues formed upon microelectronic fabrications which are fabricated employing the microelectronic fabrication processes which employ the high purity liquids. Within the art of microelectronic fabrication, such detrimental residues otherwise generally contribute to compromised microelectronic fabrication yield and/or compromised microelectronic fabrication reliability when fabricating microelectronic fabrications.
While high purity liquids are thus desirable and often essential within the art of microelectronic fabrication in order to ultimately provide microelectronic fabrications with enhanced yield and enhanced reliability, high purity liquids are nonetheless typically not provided entirely without difficulties within the art of microelectronic fabrication. In that regard, it is known in the art of microelectronic fabrication that high purity liquids are often difficult to both: (1) form with a high purity level; and (2) subsequently maintain at the high purity level, since in particular exposure of a high purity liquid to an ambient environment, a contaminating processing apparatus or a contaminating distribution apparatus will often provide for an accelerated deterioration of the purity level of the high purity liquid when employed for fabricating a microelectronic fabrication.
It is thus towards the goal of providing for use within the art of microelectronic fabrication an apparatus which assists in providing for enhanced purity integrity of high purity liquids that the present invention is directed.
Various apparatus have been disclosed in the art of microelectronic fabrication for providing an enhanced purity integrity of high purity liquids which are employed in the art of microelectronic fabrication or maintaining the enhanced purity integrity of high purity liquids which are employed in the art of microelectronic fabrication.
For example, Carr et al., in U.S. Pat. No. 5,167,808, discloses a deionized water purification system which may be continuously operated and employed for providing high purity deionized water which in turn may be employed for fabricating a microelectronic fabrication. In order to realize the foregoing object, the deionized water purification system employs, among other components: (1) a pair of sub-micrometer pre-filters, positioned in parallel, such that one of the sub-micrometer pre-filters may be changed while the other of the sub-micrometer pre-filters is employed for continuously filtering a source of deionized water to form a source of sub-micrometer pre-filtered deionized water which is employed in forming the high purity deionized water, in conjunction with; (2) a continuous purge of an upstream flow of the source of sub-micrometer pre-filtered deionized water from an ultrafilter which is downstream from the pair of sub-micron pre-filters, such as to minimize contaminant buildup upon the ultrafilter and related downstream piping.
In addition, Beppu, in U.S. Pat. No. 5,311,904, discloses a valve which may be employed within a high purity liquid piping system which in turn may be employed in providing a high purity liquid employed in fabricating a microelectronic fabrication, where the valve when connected to a branch pipe within the high purity liquid piping system which is in turn connected to a main pipe within the high purity liquid piping system prevents stagnation of a high purity liquid within the branch pipe within the high purity liquid piping system under circumstances where the valve employed within the high purity liquid piping system is closed. In order to effect the foregoing result, the valve incorporates inserted into an end of the branch pipe upon which is connected the valve and extending into the main pipe to which the branch pipe is connected a diverter member which continuously diverts a flow of the high purity liquid into and out of the branch pipe, even when the valve employed within the high purity liquid piping system is closed.
Finally, Yokoyama, in U.S. Pat. No. 5,476,118, similarly discloses a high purity liquid piping system which may be employed in providing a high purity liquid which may be employed in fabricating a microelectronic fabrication, wherein the high purity liquid piping system prevents stagnation of the high purity liquid within the high purity liquid piping system regardless of whether a valve which is connected to the high purity liquid piping system is open or closed. In order to effect the foregoing result, the high purity liquid piping system employs at an upstream side of the valve which is connected to a main pipe within the high purity liquid piping system a proximal end of a bypass pipe thus interposed between the valve and the main pipe, where a distal end of the bypass pipe reconnects with the main pipe at a downstream location of the main pipe, at which downstream location there is incorporated into the main pipe a flow restricter, such that a flow of the high purity liquid through the bypass pipe is facilitated.
Desirable in the art of microelectronic fabrication are additional apparatus which assist in providing for enhanced purity integrity of high purity liquids which may be employed in fabricating microelectronic fabrications.
It is towards the foregoing object that the present invention is directed.
A first object of the present invention is to provide an apparatus for providing a high purity liquid for use when fabricating a microelectronic fabrication.
A second object of the present invention is to provide an apparatus in accord with the first object of the invention, wherein the apparatus provides for enhanced purity integrity of the high purity liquid.
A third object of the present invention is to provide an apparatus in accord with the first object of the present invention and the second object of the present invention, which apparatus is readily commercially fabricated.
In accord with the objects of the present invention, there is provided by the present invention an apparatus for storage of a liquid. The apparatus comprises a storage tank, where the storage tank has formed integral thereto and in fluid communication therewith both a liquid inlet port and a liquid outlet port. The storage tank also has formed integral thereto and in fluid communication therewith both a gas inlet port and a gas outlet port. Finally, the gas outlet port has connected thereto and in fluid communication therewith a floating plug valve.
Within the present invention, the floating plug valve comprises a first plug movably positioned over and sealing a first aperture within the floating plug valve such that a first weight of the first plug and a first area of the first aperture define an upper operating pressure of a gas introduced into the storage tank through the gas inflow port.
The present invention also contemplates a floating plug valve which may be employed within the apparatus of the present invention.
The present invention provides an apparatus for providing a high purity liquid for use when fabricating a microelectronic fabrication, wherein the apparatus provides for enhanced purity integrity of the high purity liquid. The present invention realizes the foregoing objects by employing in conjunction with a storage tank for storage and dispensing of a high purity liquid which may be employed when fabricating a microelectronic fabrication a floating plug valve connected to and in fluid communication with a gas outlet port similarly integral to and in fluid communication with the storage tank, where the floating plug valve comprises a first plug movably positioned over and sealing a first aperture within the floating plug valve such that a first weight of the first plug and a first area of the first aperture define an upper operating pressure of a gas introduced into the storage tank through a gas inlet port which is also integral to and in fluid communication with the storage tank.
The apparatus of the present invention is readily commercially fabricated. As will become clear within the context of the Description of the Preferred Embodiment which follows, an apparatus in accord with the present invention may be readily fabricated employing components and materials which are readily available within, or readily adapted to, at least the art of microelectronic fabrication. Thus, the apparatus of the present invention is readily commercially fabricated.